Question

Which of the following involves a transfer of electrons?

PCl3 + Cl2 → PCl5
CO2 + 2LiOH → Li2CO3 + H2O
FeCl2 + 2NaOH → Fe(OH)2 + 2NaCl
NaOH + HCl → NaCl + H2O

Answer 1

To determine which of the given reactions involves a transfer of electrons, we need to look for redox reactions where oxidation states of atoms change, indicating that electrons are being transferred.

1. **PCl3 + Cl2 → PCl5**
- In this reaction, phosphorus is oxidized from +3 in PCl3 to +5 in PCl5, and chlorine is reduced from 0 in Cl2 to -1 in PCl5. Therefore, this reaction involves a transfer of electrons.

2. **CO2 + 2LiOH → Li2CO3 + H2O**
- This reaction does not involve a change in oxidation states of the elements involved; thus, it does not involve a transfer of electrons.

3. **FeCl2 + 2NaOH → Fe(OH)2 + 2NaCl**
- In this reaction, iron remains in the +2 oxidation state throughout, thus there is no transfer of electrons.

4. **NaOH + HCl → NaCl + H2O**
- This is an acid-base neutralization reaction. There are no changes in oxidation states, so no electrons are transferred.

Based on the analysis, the reaction that involves a transfer of electrons is:

**PCl3 + Cl2 → PCl5**.